Nearly everyone will have watched a TV programme and film or heard a top 10 single made in a Level Acoustic-designed facility. Company founder Chris Walls started his acoustic design consultancy specialising in high-end studio design out of his passion for good sound. The company has acquired a reputation for designing great sounding studios, even in challenging locations and more recently has been faced with the added complication of designing professional-grade studios in small spaces.

“Music, film and television production have traditionally been carried out in large purpose-built studios, which makes sense from an acoustic point of view; large rooms generally sound better than small rooms,” said Walls. “We have been lucky to design quite a few large studios, however they are becoming increasingly rare because of high property values and the capital cost of constructing, equipping and maintaining studios. It is not surprising that there is an increasing trend towards the use of smaller spaces in which the majority of audio work can be completed, occasionally moving to larger facilities for specific recording tasks or final mixing.”

The first and most important task in every project is to understand the client’s operational requirements and understand how the studio needs to perform acoustically.

“There are a few inherent acoustic limitations in small rooms which require particular attention during design to achieve good acoustic performance, including low frequency anomalies caused by room modes, colouration due to reflections from room boundaries and equipment,” adds Walls. “It’s all about being able to achieve a balanced energy response within the room.”

Having been involved with the design of more than 70 recording studios at Tileyard Studios, Level Acoustic Design is familiar with the challenges a small space creates. “The most recent Tileyard project was to emulate the sound of one of its larger studios but in a much smaller volume. That led to a few new design ideas which proved to be very successful and have since been implemented elsewhere. We designed the live room walls and ceiling to achieve a particular early reflection pattern which makes the studio sound bigger than it actually is. It means you can add a fairly luxuriant reverb to anything recorded in there and it melds very well because of the rooms’ early reflection signature.”

Some of the challenges faced when designing a small studio include low frequency monitoring accuracy which is largely dictated by the modal behaviour of the room. Room modes are frequencies whose wavelengths have a simple correlation with the room geometry and at these frequencies the amplitude response is significantly affected. Modes are generally quite spread out at low frequencies, which gives rise to an uneven amplitude response, with some frequencies being supported by modes and others not. “It is quite common for small studios to have pronounced modal behaviour in to the low mid frequency region,” continues Walls. “When designing small studios, it is particularly important to deal with the prominent modal frequencies to ensure they do not adversely affect the monitoring response. Where space is limited, this can only be achieved using resonant absorbers such as membrane, Helmholtz or panel absorbers; foam and Rockwool will do very little to help at these frequencies! It is possible to mitigate the worst of the room mode effects, but careful design is key to achieving good translation between small studios, large studios and ultimately the consumer’s playback format”.

Level Acoustic Design recently completed a project for Molinare Post Production, completely refurbishing an existing 5.1 mix studio and upgrading the monitoring to 7.1 with Atmos HE and premix capabilities. “The commercial requirement for immersive audio has definitely increased over the last couple of years with US productions in particular starting to explore Atmos HE for home entertainment releases,” adds Walls. “We have designed quite a few small Atmos rooms to serve this market in the past six months and our focus has been on maintaining the acoustic quality in these smaller spaces. This is part of an ongoing trend of trying to squeeze more and more out of smaller and smaller spaces – it’s not unusual to walk in to a 10m studio with monitors that go down to 25Hz. That is generally not a recipe for success!”

In music, many artists and producers are building their own small, private studios. Level Acoustic Design continues to refine designs to eke out every last bit of performance while educating clients as to what can realistically be achieved in a small room.

“The brief is typically for a modestly-sized, relaxing space which doesn’t necessarily feel like a studio, however there is still the expectation that they can accurately monitor and mix, which throws up some challenges in balancing layout and aesthetics with acoustic performance.

“Reflections pose a challenge in small mixing rooms as they arrive at the mix position sooner and stronger in a small room than a large room due to the closer proximity of the partitions.” Strong, early reflections will combine with the sound arriving directly from the loudspeakers and cause errors in the frequency response and stereo imaging.

“Acoustic treatment in small rooms must be designed to attenuate early reflections such that they do not adversely affect the direct sound, which in practice means attenuating them by at least 10dB relative to the direct sound.” Another reflection-based problem is the boundary interference effect, whereby sound emanating from a loudspeaker is reflected by nearby surfaces and arrives back at the loudspeaker with a 180° phase shift causing cancellation and a resulting notch in the frequency response.

“In a large room it is often possible to position the loudspeakers far enough from room boundaries that the notch is below the speaker’s cut-off frequency, however in small rooms the notch frequency will generally be in the 80Hz – 150Hz region and there will often be several notches relating to several nearby boundaries,” says Walls.

“Dealing with boundary interference effects in small rooms can be tricky but considered positioning of loudspeakers can usually give a satisfactory low frequency response.” The solutions to designing a small room generally involve using acoustic treatment to absorb sound in the room. “It is important when designing the absorption in any room that a suitable balance of low, mid and high frequency energy is maintained. If a room, particularly a small room, is treated solely with foam or mineral wool panels (which absorb primarily high frequencies) it will tend to have a lot of low frequency energy and very little mid and high frequency energy. This is generally what has happened when people complain of rooms sounding ‘boomy’.

“When it comes to studio room acoustics, bigger is generally better. Designing small studios largely involve mitigating potential problems thrown up by the reduced size, however with careful design it is possible to achieve a small studio which enables accurate monitoring and translates well to larger studios and the final delivery format – as well as a really great space.”